What is CLAM
Applies to
- ONTAP 9
- Connectivity, Liveness, Availability Monitor (CLAM)
Answer
Connectivity, Liveness, Availability Monitor (CLAM), is a feature of ONTAP used to monitor connectivity and state of all nodes in the cluster, alert admins of changes, and possibly, take action by takeover.
- CLAM monitors all nodes in the cluster and determines for each:
- Administrative state (enabled/disabled)
- Operation state (connected, live, available)
- HA takeover status
- Cluster quorum status
- CLAM alerts admins about manual actions such as:
- Node reboot
- Node takeover
- Node shutdown
Note: Except for the node the action was one, each node in the cluster will send a Node Out of Quorum AutoSupport message.
- CLAM alerts admins about unexpected state changes:
- Power loss
- Cluster network connection loss
- Other node unresponsive events
Note: Except for the node with the issue, each node in the cluster will send a Node Out of Quorum AutoSupport message.
- When CLAM determines a node is not responding (out of quorum), it will:
- Send a Node Out of Quorum AutoSupport message from each available node in the cluster.
- Initiate an HA takeover of the node if it continues failing to respond.
- Generate a memory dump of the node targeted for takeover.
- The target node will generate a message similar to:
PANIC: Received PANIC packet from partner, receiving message is (Coredump and takeover initiated because Connectivity, Liveliness and Availability Monitor (CLAM) has determined this node is out of quorum.)
- Clam monitoring and takeover is enabled by default on:
- All systems using ONTAP 9.8 and later.
- SAN enabled systems using ONTAP 9.7 and earlier.
Additional Information
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